Reflexes and Receptors

What are receptors in the body?

Structures that detect changes in the body’s internal or external environment.

What is an example of a grouped receptor in a sense organ?

The eye, which contains light receptors.

How do receptors send signals to the body?

When stimulated, receptors enable the body to respond to changes, sometimes through automatic reflexes.

What do thermoreceptors respond to?

Heat and cold.

Where are peripheral thermoreceptors found?

In the skin and some mucous membranes.

What is the role of thermoreceptors in the hypothalamus?

To monitor core body temperature by detecting blood temperature.

What do osmoreceptors sense?

Osmotic pressure, related to the concentration of substances in blood plasma.

What is the function of chemoreceptors in the nose?

To detect odors.

What is the function of chemoreceptors in the mouth?

To sense tastes.

Where are touch receptors primarily located?

Mainly in the skin.

Do touch receptors adapt over time?

Yes, touch receptors close to the skin surface and those attached to hairs adapt rapidly.

What are nociceptors?

Pain receptors that warn the body of tissue damage.

How do pain receptors respond to stimulation?

They do not adapt and continue to send signals as long as the stimulus is present.

What is the function of stretch receptors?

To respond to the stretching of surrounding muscle tissue.

What is a reflex?

A rapid, automatic response to a change in the environment.

What are the properties of all reflexes?

Stimulus required, involuntary, rapid response, stereotyped reaction.

What is a spinal reflex?

A reflex processed by the spinal cord alone.

What is a reflex arc?

The pathway a nerve impulse follows from a receptor to an effector.

What are the components of a reflex arc?

Receptor, sensory neuron, synapse, motor neuron, effector.

What happens during a simple reflex arc involving 3 neurons?

Response occurs quickly while simultaneously sending impulses to the brain.

What are innate reflexes?

Automatic, instinctive reactions present from birth.

What are acquired reflexes?

Complex motor patterns learned through repetition.

What are some similarities between hormonal and nervous coordination?

Some substances act as both hormones and neurotransmitters, and certain hormones are secreted by neurons.

What is the nature of messages in the nervous system?

Electrochemical (electrical impulses and neurotransmitters).

How are messages transmitted in the endocrine system?

Through chemicals (hormones) in the bloodstream.

Which cells are affected by the nervous system?

Muscle and gland cells, and other neurons.

Which cells are affected by the endocrine system?

All body cells.

How fast is the response time for the nervous system?

Rapid, within milliseconds.

How long do responses last for the nervous system compared to the endocrine system?

Nervous responses are brief, while endocrine responses are longer-lasting.

What is an example of a protective reflex present from birth?

Suckling.

What type of reflex involves voluntary muscle adjustments?

Acquired reflexes.

Which receptors are sensitive to osmotic pressure changes?

Osmoreceptors.

What do chemoreceptors in blood vessels respond to?

pH of blood and concentrations of O2 and CO2.

What is the function of pain receptors?

To warn about potential tissue damage and allow for reactions to minimize injury.

What are touch receptors that respond to light touch called?

Mechanoreceptors sensitive to very light touches.

What is the role of the hypothalamus regarding temperature?

It receives information from thermoreceptors to regulate body temperature.

In what areas are touch receptors greater in concentration?

Sensitive areas such as lips, fingertips, and eyelids.

What happens to the nerve impulses during a spinal reflex?

Impulses are sent to the motor neuron without requiring immediate input to the brain.